Gestational diabetes (GDM) is one of the most common complications in pregnancy, with a prevalence that continues to rise. At the time of the COVID-19 epidemic, immediate reorganisation and adjustment of the system was needed. Telemedicine support was offered in order to provide high-quality treatment to pregnant women. However, the success of the treatment is unknown. We therefore aimed to evaluate COVID-19 epidemic effects on pregnancy outcomes in GDM. The maternal outcomes (insulin treatment, gestational weight gain, caesarean section, hypertensive disorders) and perinatal outcomes (rates of large and small for gestational age, preterm birth and a composite child outcome) of women visiting a university hospital diabetes clinic from March to December 2020 were compared with those treated in the same period in 2019. Women diagnosed with GDM during the COVID-19 epidemic (n=417), were diagnosed earlier (23.9 11.7-26.0 vs. 25.1 21.8-26.7 gestational week), had higher fasting glucose (5.2 5.0-5.4 vs. 5.1 4.8-5.3 mmol/l) and earlier pharmacological therapy initiation, and had achieved lower HbA1c by the end of followup (5.1% (32.2 mmol/mol) 4.9% (30.1 mmol/mol)-5.4% (35.0 mmol/mol) vs. 5.2% (33.3 mmol/mol) 5.0% (31.1 mmol/mol) - 5.4%·(35.5 mmol/mol), p<0.001) compared to a year before (n=430). No significant differences in perinatal outcomes were found. Although GDM was diagnosed at an earlier gestational age and higher fasting glucose concentration was present at the time of diagnosis, the COVID-19 epidemic did not result in worse glucose control during pregnancy or worse pregnancy outcomes in Slovenia.